a new Genus of Graptolites. 25 
tive characters of these two Graptolites demonstrates at once, 
as shown by the annexed diagrammatic sketches, the follow- 
ing fundamental differences :—Pleurograpsus is distinguished 
by the total absence of anything like a “ funicle,” by the 
“irregular ’’ manner in which the branches are given off from 
opposite sides of the main celluliferous stipes, and by the pre- 
sence of secondary branches. Helicograpsus, on the other 
hand, is characterized by the possession of a long and remark- 
ably distinct funicle, by the. regular and definite plan upon 
which the branches are given off, and by the absence of se- 
condary offsets. 
Fig. 2. 
Fig. 1. Sketch of Helicograpsus gracilis, Hall, sp.: a, radicle; 6, funicle. 
Fig. 2. Sketch of Pleurograpsus linearis, Carr., sp. 
As the above-mentioned distinctions are as broad and as 
weighty as those which separate any of the genera of the 
Graptolitide from each other, there can be no hesitation in 
following the usual rule in the case of Pleurograpsus and 
Helicograpsus. 
Hitherto one Graptolite only has been discovered which can 
